Techniques and systems are known for correcting and stabilizing bones, including the bones of the spine. Stabilization of the spine for various conditions, such as degenerative disk disease, scoliosis, spondylolisthesis, and spinal stenosis, by way of example, often require attaching implants to the spine and then securing the implants to spinal rods. Such spinal fixation devices can immobilize the vertebrae of the spine and can alter the alignment of the spine over a large number of vertebrae by connecting at least one elongate rod to the sequence of selected vertebrae. These rods can span multiple vertebrae. The spine anatomy, however, rarely allows for three or more implants to be directly in line. In order to allow for this irregularity, the rod must be contoured to the coronal and sagittal planes.
Spinal fixation has become a common approach in fusion of vertebrae and treating fractures and the above listed spinal disorders. A common device used for spinal fixation is a bone fixation plate assembly. Typical bone fixation plate assemblies have a relatively flat, rectangular plate with a plurality of apertures therethrough. Another option is an implant fixation system that locks a rod to several vertebrae. In these systems, as with other spinal fixation systems, various fasteners, such as bone screws and spacers, are used to secure the implant fixation assembly to the desired and targeted vertebrae of the patient. These screws vary in design and shape, depending upon their desired location and use.
Screws, such as polyaxial, monoaxial, and uniaxial screws, are frequently used as fasteners in implantation fixation systems. Once these screws are set in a desired position, the screws are securely fixed in that position to minimize or eliminate movement of the vertebra. This is typically accomplished with a fixation system that securely engages the screw.
When screws are applied to a bone, multiple steps may be performed to apply the screw. First, an initial pilot hole may be made in the bone by an awl for placement of the screw. Then, a drill bit may be used to extend the pilot hole, and in some cases the hole may be tapped. Then, the screw can be applied into the tapped hole. This sequence requires the use of three separate steps and instruments, plus a driver for placing the screw into the tapped hole. Switching from instrument to instrument takes time and there are often challenges in locating the hole placed within the soft and the boney tissue. Each added step increases the time, and thus risk of infection, as new instruments are passed into the surgical site. In addition, current instruments can have variable levels of surgical effectiveness due to loss of sharpness following use in multiple cases and/or re-processing (e.g., awl, drill or tap, or driver tip) or due to drift in torque limiting features following re-processing. Lastly, current non- or pre-sterile screws often require the operating room staff to handle and touch the devices increasing risk of infection and/or damage to the clinician's gloves.